// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019 TDK-InvenSense, Inc.
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/regmap.h>
#include <linux/delay.h>
#include "inv_mpu_aux.h"
#include "inv_mpu_iio.h"
/*
* i2c master auxiliary bus transfer function.
* Requires the i2c operations to be correctly setup before.
*/
static int inv_mpu_i2c_master_xfer(const struct inv_mpu6050_state *st)
{
/* use 50hz frequency for xfer */
const unsigned int freq = 50;
const unsigned int period_ms = 1000 / freq;
uint8_t d;
unsigned int user_ctrl;
int ret;
/* set sample rate */
d = INV_MPU6050_FIFO_RATE_TO_DIVIDER(freq);
ret = regmap_write(st->map, st->reg->sample_rate_div, d);
if (ret)
return ret;
/* start i2c master */
user_ctrl = st->chip_config.user_ctrl | INV_MPU6050_BIT_I2C_MST_EN;
ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
if (ret)
goto error_restore_rate;
/* wait for xfer: 1 period + half-period margin */
msleep(period_ms + period_ms / 2);
/* stop i2c master */
user_ctrl = st->chip_config.user_ctrl;
ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
if (ret)
goto error_stop_i2c;
/* restore sample rate */
d = st->chip_config.divider;
ret = regmap_write(st->map, st->reg->sample_rate_div, d);
if (ret)
goto error_restore_rate;
return 0;
error_stop_i2c:
regmap_write(st->map, st->reg->user_ctrl, st->chip_config.user_ctrl);
error_restore_rate:
regmap_write(st->map, st->reg->sample_rate_div, st->chip_config.divider);
return ret;
}
/**
* inv_mpu_aux_init() - init i2c auxiliary bus
* @st: driver internal state
*
* Returns 0 on success, a negative error code otherwise.
*/
int inv_mpu_aux_init(const struct inv_mpu6050_state *st)
{
unsigned int val;
int ret;
/*
* Code based on the vendor Linux kernel v3.0,
* the exact meaning is unknown.
*/
if (st->chip_type == INV_MPU9150) {
unsigned int mask = BIT(7);
val = st->level_shifter ? mask : 0;
ret = regmap_update_bits(st->map, 0x1, mask, val);
if (ret)
return ret;
}
/* configure i2c master */
val = INV_MPU6050_BITS_I2C_MST_CLK_400KHZ |
INV_MPU6050_BIT_WAIT_FOR_ES;
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_MST_CTRL, val);
if (ret)
return ret;
/* configure i2c master delay */
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV4_CTRL, 0);
if (ret)
return ret;
val = INV_MPU6050_BIT_I2C_SLV0_DLY_EN |
INV_MPU6050_BIT_I2C_SLV1_DLY_EN |
INV_MPU6050_BIT_I2C_SLV2_DLY_EN |
INV_MPU6050_BIT_I2C_SLV3_DLY_EN |
INV_MPU6050_BIT_DELAY_ES_SHADOW;
return regmap_write(st->map, INV_MPU6050_REG_I2C_MST_DELAY_CTRL, val);
}
/**
* inv_mpu_aux_read() - read register function for i2c auxiliary bus
* @st: driver internal state.
* @addr: chip i2c Address
* @reg: chip register address
* @val: buffer for storing read bytes
* @size: number of bytes to read
*
* Returns 0 on success, a negative error code otherwise.
*/
int inv_mpu_aux_read(const struct inv_mpu6050_state *st, uint8_t addr,
uint8_t reg, uint8_t *val, size_t size)
{
unsigned int status;
int ret;
if (size > 0x0F)
return -EINVAL;
/* setup i2c SLV0 control: i2c addr, register, enable + size */
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0),
INV_MPU6050_BIT_I2C_SLV_RNW | addr);
if (ret)
return ret;
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg);
if (ret)
return ret;
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),
INV_MPU6050_BIT_SLV_EN | size);
if (ret)
return ret;
/* do i2c xfer */
ret = inv_mpu_i2c_master_xfer(st);
if (ret)
goto error_disable_i2c;
/* disable i2c slave */
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
if (ret)
goto error_disable_i2c;
/* check i2c status */
ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);
if (ret)
return ret;
if (status & INV_MPU6050_BIT_I2C_SLV0_NACK)
return -EIO;
/* read data in registers */
return regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA,
val, size);
error_disable_i2c:
regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
return ret;
}
/**
* inv_mpu_aux_write() - write register function for i2c auxiliary bus
* @st: driver internal state.
* @addr: chip i2c Address
* @reg: chip register address
* @val: 1 byte value to write
*
* Returns 0 on success, a negative error code otherwise.
*/
int inv_mpu_aux_write(const struct inv_mpu6050_state *st, uint8_t addr,
uint8_t reg, uint8_t val)
{
unsigned int status;
int ret;
/* setup i2c SLV0 control: i2c addr, register, value, enable + size */
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0), addr);
if (ret)
return ret;
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg);
if (ret)
return ret;
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(0), val);
if (ret)
return ret;
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),
INV_MPU6050_BIT_SLV_EN | 1);
if (ret)
return ret;
/* do i2c xfer */
ret = inv_mpu_i2c_master_xfer(st);
if (ret)
goto error_disable_i2c;
/* disable i2c slave */
ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
if (ret)
goto error_disable_i2c;
/* check i2c status */
ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);
if (ret)
return ret;
if (status & INV_MPU6050_BIT_I2C_SLV0_NACK)
return -EIO;
return 0;
error_disable_i2c:
regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
return ret;
}
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